Wednesday, July 09, 2014

An international team of astronomers has developed a 3D model of a giant cloud ejected by the massive binary system Eta Carinae during its 19th century outburst. Eta Carinae lies about 7,500 light-years away in the southern constellation of Carina and is one of the most massive binary systems astronomers can study in detail. The smaller star is about 30 times the mass of the sun and may be as much as a million times more luminous. The primary star contains about 90 solar masses and emits 5 million times the sun's energy output. Both stars are fated to end their lives in spectacular supernova explosions.

A
new shape model of the Homunculus Nebula reveals protrusions, trenches,
holes and irregularities in its molecular hydrogen emission. The
protrusions appear near a dust skirt seen at the nebula's center in
visible light (inset) but not found in this study, so they constitute
different structures.

Friday, March 30, 2012

At the turn of the 19th century, the binary star system Eta Carinae
was faint and undistinguished. In the first decades of the century, it
became brighter and brighter, until, by April 1843, it was the second
brightest star in the sky, outshone only by Sirius (which is almost a
thousand times closer to Earth). In the years that followed, it
gradually dimmed again and by the 20th century was totally invisible to
the naked eye.

The star has continued to vary in brightness ever
since, and while it is once again visible to the naked eye on a dark
night, it has never again come close to its peak of 1843.

The
larger of the two stars in the Eta Carinae system is a huge and unstable
star that is nearing the end of its life, and the event that the 19th
century astronomers observed was a stellar near-death experience.
Scientists call these outbursts supernova impostor events, because they
appear similar to supernovae but stop just short of destroying their
star.

Although 19th century astronomers did not have telescopes
powerful enough to see the 1843 outburst in detail, its effects can be
studied today. The huge clouds of matter thrown out a century and a half
ago, known as the Homunculus Nebula, have been a regular target for
Hubble since its launch in 1990. This image, taken with the Advanced
Camera for Surveys High Resolution Channel is the most detailed yet, and
shows how the material from the star was not thrown out in a uniform
manner, but forms a huge dumbbell shape.

Eta Carinae is not only
interesting because of its past, but also because of its future. It is
one of the closest stars to Earth that is likely to explode in a
supernova in the relatively near future (though in astronomical
timescales the “near future” could still be a million years away). When
it does, expect an impressive view from Earth, far brighter still than
its last outburst: SN 2006gy, the brightest supernova ever observed,
came from a star of the same type.

This image consists of
ultraviolet and visible light images from the High Resolution Channel of
Hubble’s Advanced Camera for Surveys. The field of view is
approximately 30 arcseconds across.

For me this image is related to something proposed by someone else in terms of self similarity. The idea that what we might see on the microscopic level may some how be transferred to a larger rendition of that happening. I thought that appealing in a way as to how one might have mapped the star systems to orbitals and how we look look at the larger versions displayed in the cosmos.